Snap locking slab



Get. .1, 1935. a, DAVIS 2,015,744

3 Sheets-Sheet 1 Oct. 1, 1935. c. F. DAVIS 2,015,744

SNAP LOCKING SLAB Filed Feb. 20, 1933 3 Sheets-Sheet 2 Oct. 1, 1935. c. F. DAVIS 5,

' SNAP Locum SLAB Filed Feb. 20, 1953 5 Sheet-Sheet s ATTORNEY.

Patented 1, 1935 curse E. Davis,

mesne snort nun, N. 1., mama by cuts, to American Cyanamid &

Chemical Corporation, a corporation of Delaware hpplicationFcbruary 20, 1933, SerialNo. 657,567"

. e atoms. The present invention relates to a precast slab having a body'of set cementitious material of which gypsum is typical,*carrying means thereon to inter-engage a corresponding slab when the a such slabs.

fromany reason,

two are erected together, as by means of a snap lock, and to a building construction including While the invention is particularly concerned and is primarily directed to a slab ofthe above type which may be used for ceilings or the like,

yet the invention is, of course, not to be restricted thereto as it is to be distinctly understood that the slab of this invention may be used in any other location as for instance in floor, roof, wall or in fact any situation where the particular structure thereof will be of advantage.

In building constructions using slabs of the precast variety,

it is extremely desirable'that when such slabs are used as a suspended ceiling, that means be provided to insure that the contiguous series of slabs are perfectly level, thatis, the bottom faces'thereof are in the same plane, that each slab, be held securely to its neighbor without undue separation, and that contiguous slabs be held with relation to each other in such a rigid manner that in the event that a plasteredsurf ace is desirable,.the plasterer, in applying the plaster as by means of a trowel orthe like, will not be able accidentally to lift one slab in'relation to its neighbor. If this accidental movement occurs cracks are liable-to develop in the eventual ceiling, which is of course undesircomplicated or cumbersome mechanism and with In constructions using a suspended slab,

also desirable that such slabs be adequately supported at all points with a minimum number of supporting elements,because an excessivenumher is not only expensive ,from the initial cost standpoint but slows up erection due, to the fact that the individual supporting or hanging ele ments must be put into place and adjustments made to positively determine their accurate location; 'I'he principal objects of the invention are, therefore, the accomplishment of the above desirable features without initially increasing the cost of the slab itself unduly, without resorting to a minimum amount of expense; time and effort.

To this end the invention in=its broadest aspect contemplates the provision of a precast slab of set cementitious material with metal members on at least two opposite edges thereof having complementary parts. Where desired all four edges of the slabmay be so It is contemplated of which gypsum is a out admixtures such as of a female element (CL-7H8) I slabs together in a substantially, rigid manner.

The inventionalso contemplates insuch a construction'the use of additional co-operating portions such as tongues and grooves, which not only to serves thepurposes of additionally securing the slabs together but permits oneslab to bepositive- 1y supported by the other slab, all of which makes for a more satisfactory, rigid and fool-proof constructien. 15

Where a complete fireproof structure is desired, these metal members may be so arranged within the. body'of the slab that a substantial body of the cementitious material suchas gypsum will cover them and protect the'same against the ravages of This is desirable, although not essentiaL. e a

In the drawings- 1 a Fig. 1 is a sectional view the slabsof the invention.

h Fig. 2 is a perspective view of a single slab.

, Fig. 3 is a sectional viewof a modified slab.

Fig.4 is a similar view of another form of slab. Fig. 5 is a similar view of another form of slab. Fig. 6 is a similar view of another form of slab. M Fig. '7 is a similar view of another form of slab. Fig. 8 is a similar view of another form of slab. i

Fig. 9 is a fragmentary perspective view of another form of slab showing the method of interlock. v i

In the drawings such aslab is shown to consist of the body I of set cementitious material type, either with or withwood chips, and of any 40 desired thickness and other dimensions. This slabbody has applied toqone edge portion thereindicated generally at 2 having a groove 3 with a forward depending lip of a ceiling involving 4, and anupstanding flange-i perforated as at I,

The opposite end of the metal member 2 is; formed into a ledge portion 1 and the end is turned back into the slab body I as at 8. Where desired, the end 8 may be expanded or per- :forated to permit the which the bodyl is made to penetrate the same andassist in bonding the metal thereto.

At the opposite edge cementitious material of l of the slabs-i isa male a member indicated generally at 9 having a pro jection 10 with a collapsible portion II. The e specified in connection with to correspond with the 2 1 opposite end of the metal member embedded inthe body I as at it will be. apparent that a slab A having been erected as for instance in aceiling orthe like, the slab B is then merely shoved up against the slab A so that the metal projection I0 passes through the restricted throat in the-recess 3, the eollapsible portion ll passing thereunder and then automatically springing out into the recess Beyond the lip l. The ledge 1 in the slab A fits in the cut away portion I! of the slab B and hence'the parts are closelyr fitted together. This arrangement insures against any accidental separation of the two slabs, and insures a tight Joint between the parts.

The perforations 6 on the upstanding flange 5 of the slab A may receive suitable hanging deintersect the arc ment.

vices H which may either pass around a furring strip l5 which is in turn suspended from suitable supports l6 or such slabs may be suspended directly from the supports 16 as circumstances will dictate. Due to the fact that the flange 5 has-a series of such perforations 6, no particularly regard need be given to the arrangement of such slabs as the hooks I4 may be inserted in the nearest perforation to the particular point of support desired.

The collapsible portion ll on the male projection should, of course, be of such dimensions as will permit the same to automatically spring up beyond the throat into the recess 3 and engage the shoulder definedjbythe metal lip to prevent the same from being accidentally withdrawn therefrom.

While in the preferred form of the invention the recess 3 is substantially rectangular in crosssection, yet obviously this either may be rounded as in Fig. 3 or given any other configuration desired to produce the above result. In order to prevent any undue movement between slabs, the male projection l0 may be provided with a step I! as shown in Fig. 4, which is adapted to underlie the lip 4 and make substantial" contact therewith. This insures that the parts will fit tightly together without undue relative movement. v

In some cases it will .be found more expedient to arrange the upper wall of the recess 3 in the form of an inclined plane as at l8, Fig. 5, it being only necessary that this'surface penetrate or X defined by the end of the collapsible portion II in its movement. Such a construction insures the tight fitting of the collapsible portion II in the recess 3 when the Parts are pressed together and takes up any irregularities in manufacture that may exist." a

In the above forms it is to be noted that the slab Bis supported solely by reason of the stiffness of the metal defining the niale projection III. In cases, where to make this a gaugeas will give requisite stiffness would be too expensive, an additional projection such as a tongue l9 may be placed on the slab B, which will inter-engage with a corresponding groove 20 on slab A. In this manher'any undue strain is taken off of the projection i0 and the entire edge of the slab B may be supported on the slab A by reason of its tongued and grooved engage- Various forms of tongues and grooves may be used as for instance the. tapered tongue metal of such standpoint of being firep separation of the metal from the slab 2| and corresponding groove of Fig. 8 or the entire section below the recess 3 may be utilized as a tongue as at 22, Fig. 6.

Where additional rigidity is desired, the male projection l0 may likewise be provided with an 5 upstanding flan ge 22 adapted to lie alongside of the projections and if necessary secured thereto either by means of the supporting members I! or otherwise as desired.

In all events it is desirable to extend the ulti- 10 15 It is desirable, of course, that the top of the.

flanges 5 and", or eitherof them, above the upper surface of the slab to which it is attached and for this purpose the tops of the slabs adjacent such projections are as shown to render such flange or flanges accessible. 'while this is desirable, yet it is not absolutely essential.

In those slabs where the metal members are embedded in the slab body anddo not project down to a point near the undersurface thereof, such slabs. are particularly of value from. the As indicated, there is a substantial body of the set cementitious material below the metal itself where the same is of gypsum or the like, is particularly eflicacious for these purposes.

In circumstances, however, where only a semiflreproof construction is desired or no regard need be paid to the ability metal members may extend all the way down te the under surface of the slab and along that surface. In such events it is desirable that the end of the metal be returned into the body of the slab as at 24. This prevents any not project body.

In erecting such a construction into a ceiling,

the first slab may be abutted close to a wall or the like 25. In such case-a wire or hairpin 26 may be threaded through an aperture 21 in the metal member I, and passed around the furring strip I5 to support that edge of the slab, or a hall 28 or staple driven into the slab beneath the metal-part Ill and the wire 26 used as above; described. Of course, of supporting this edge of the slab may be used as desired, whether such edgeis cut or uncut.

Where the'slab of Fig. 9 is used, and the male projection I0- is provided with an upstanding flange 23, the supporting element I may be used 55 to carry this edge of the slab. As an alternative form, one slab may be provided with the metal members 2 on two opposite edges and this part secured in abutting relation to a wall as by nails or the like. tion, the first slab maybe erected with its part 2 against the wall and the other slabs worked in in the opposite direction.

It is contemplated, of'course, that all rooms in which such slabs are be of such a dimension number of slabs will completely fill out the same. In such event the slabs may be cut longitudinally at the point desired and the cut end supported in any of the ways described. slab is supported by means of the parts 29 and 30 nafled to the wall as at 3|.

While in many instances itwill be found unnecessary to provide the shorter ends of such slabs with these snap interlocks, yet in many cases this 75 cut away 20 and this material. 30

to withstand fire, the 35 accidental 40 any other means 5 As still another method of erec- .0

used as ceilings, will not that a predetermined In Fig. l the cut 10 two or four edges of such slabs.

. rigidit and security construction,

will be desirable and of course, the invention contemplates theapplication of these parts to either 'While ordinarily therewill be no occasion to as a matter of fact, the such an interlockis one unlatch such slabs and of of the prime features of the invention, yet in purpose.- In such been designated as collapsible, yet it will be ob-f in most cases both of complementary part, that is,

or the received portion expansible or'collapsible as having metal erected together,

case it is desired to release the latch, apertures 32 in the male element may be provided for this cases, an instrument may be hooked into such aperturesand the upstanding flange collapsed and withdrawn from the recess.

While the'part II on the male member has vious that the accommodation of this spring latch in the recess may be by reason of the expansion or enlargement of the metal element constituting the recess orthe recess itself respectively, as these parts will be made of inherently resilient material. At the same time, in. some instances it may be found desirable to make either one or the other parts rigid and the either the receiving the case may be, and hence the claims are to be construed with this in mind.-

While the invention has been shown with particular reference to the ceiling slab, yet obviously this same slab may be used as a floor, partition, roof, wall or in any situation where such a slab would be of advantage. a i

I claim:

l. A precast slab of. set cementitious material members on opposite. edge portions, said members having complementary parts, one of said members having a recess with a restricted neck, the other member having a collapsible projection adaptedto enter the corresponding recess on an adjacent slab when two such slabs are erected together, to be collapsed as it passes through the restricted neck and then automatically expand beyond the neck, with a step be tween the ends of such projection in substantial contact with the restricted neck, to positively interlock the two slabs together. 2. A precast slab of set cementitious material having metal members on opposite edge portions,

, said members having complementary parts, one

of said members having a recess with a re-' stricted neck and a second recess below the first, the other member having a collapsible projection adapted toenter the corresponding recess on an adjacent slab together, to be collapsed as it passes through the restricted neck and then automatically expand beyond the neck, and a second projection noncollapsible in nature, to enter the ,second recess on the adjacent slab, to positively interlock the two slabs together.

3. A precast slab of set cementitious material having metal members on opposite edge portions, such members having comp} of said members having a recess with a restricted neck, the other member having a collapsible projection adapted to enter the corresponding recess on an adjacent slab when two such slabs are to be collapsed as it passes through the restricted neck and then automatimember, one of said when two such-slabs are erected ementary parts, one i cally expand beyond the neck to positively interlock the two slabs together, one end of each member being embedded-in the cementitious material with a substantial body of cementitious material below the same. I

4. A precast slab of set'cementitious material having metal members onopposite edge portions,

such members having complementary parts; one

. of said members having a recess neck, the other member having a collapsible pro jection adapted to enter the corresponding recess on an adjacent slab when two such slabs are erected together, to be collapsed as it passes through the restricted neck and then automatically expand beyond the neckto positively interwith a restricted lock the two slabs together, one of said metal members having an upstanding flange.

5. A precast slab of set cementitious material having metal members on opposite edge portions, such members having complementary parts, one of said members having a recess with a restricted neck, the other member having a collapsible projection adapted to enter the corresponding recess on an adjacent slab when two such slabs are erected togeher, to be collapsed as it passes through the restricted neck and then automatically expand beyond the neck to positively inter- *lock the two slabs together, both of said metal members having upstanding flanges.

6. A building construction including two precast slabserected adjacent to each other, each slab having a metallic member co-opera ti'rig with a complementary portion of the adjacent metallic member, one of said members having a recess, the top of which is defined by an angular wall, and also having a restricted neck, the other member having a projection wit said recess and sprung up beyond the restricted neck, the end'of such projection being in contact with thetop wall of the recess. a

7. A building construction including two precast slabs erected adjacent to each other, each slab having a metallic member co-operating with a complementary portion of the adjacent metallic members having a recess with a restricted neck, the other member having a projection within the recess and sprung up beyond the neck, and a step in substantial contact with the restricted neck. 8. A building construction including two precast slabs erected slab having a metallic member cQ-hperating with a complementary portion of the adjacent metallic adjacent to each other, each.

member, one of said members having a recess a complementary portion of the adjacent metallic member, one of said members having a recess with a restricted neck, the other member having a projection sprung up into said recess beyond the neck, one end of the metal member in each slab being embedded in the pementitious material with a substantial body of cementitious material below the same. I

10. A building construction including two precast slabs erected adjaoentto each other, each slab having a metallic member co-operatingwith a complementary portion of the adjacent metallic member, one of said members having a recess .with a restricted neck, the other member having a projection sprung up into said recess beyond the neck, one of said metal members having an upstanding flange,

11. A building construction including two precast slabs erected adjacent to each other, each slab having a metallic member co-operating with a complementary portion of the adjacent metallic member, one of said members having a races with a restricted neck, the other member having a projection sprung up into said recess beyond the neck, both of said metal members having upstanding flanges.

12. A ceiling construction comprising supporting-elements, a series of precast slabs suspended below the same with their edge portions adjacent, one of said slabs having a metal member on the edgefportion thereof defining a groove with a re-' stricted neck, the adjacent slab having a metal.

member on the edge portion thereof with a projecticnwithin said recess and sprung up beyond the. restricted neck, the first metal member having an upstanding flange, and means to connect said upstanding flange to the supporting element.

' 13. A ceiling construction comprising supporting elements, a series of precast slabs suspended. below the same with their edge portions adjacent,

one of said slabs having a metal member on the edge portion thereof defining a groove with a restricted neck, the adjacent slab having a metal member on the edge portion thereof with a projction within said recess and sprung up beyond the restricted neck, the first metal member having" an upstanding flange, and means to connect said upstanding flange to the supporting element,

said slabs being additionally tongued and grooved together. w

191. A building construction including two precast slabs erected adjacent to each other, each slab having a metallic member co-operating with a complementary portion of the adjacent metallic member, one of said members having a recess member, one of said members having a recess with a restricted neck, the other member having a projection sprung up into said recess beyond the neck and means to support said slabs in which adjacent edges of two slabs are ship-lapped,

one of the ship-lapped edges of one slab being covered with metal. I

18. A building construction including two preslab having a metallic member co-operating with a complementary portion of the adjacent metallic member, one of said members having a recess with a restricted neck, the other member having a projection sprung up into said recess beyond the neck and means to support said slabs in which the recess is substantially rectangular in cross-section.

17. A building construction including two precast slabs erected adjacent to each other, each slabhaving a metallic member co-operating with A a complementary portion of the adjacent metallic member, one of said members having a recess with a restricted neck, the other member having a projection sprung up into said recess beyond the neck and means to support said slabs in which the recess is substantially triangular'incross section. I I

18. The slab of claim 4 in which the upstanding flange is free of cementitious material. 19. The slab of claim 4 in which'the upstanding flange is free of cementitious material and terminates short of a plane including the upper slab face.

20. The combination of claim 12 in which one slab is supported at one edge solely by the inter-.

locking engagement with the adjacent slab.

21. The combination of claim 10 in which the formed by adjacent cutaway po tions of adjacent slabs.

upstanding flange is located within a groove 40 22. "A building construction including two precst-slabs erected adjacent to each other, each slab having a metallic member co-operating with ,a complementary portion of the adjacent metallic member, one of said members having a recess with a restricted neck, the other member having a projection sprung up into said recess beyond the neck and means to support said slabs in which one slab is supported at one edge solely by the edge oi the adjacent slab.

CLARKE F. DAVISs 

